1. Field
The present invention relates generally to communication systems. More particularly, this invention relates to a system and method for providing privacy of user identity and characteristics in a communication system.
2. Background
Recently, there has become a need in the telecommunications industry to provide secure communications in both wireless and wireline communication systems. With the advent of wireless telephony, the ability to provide secure communications have become even more important, due to the ubiquitous nature of electromagnetic signals.
In prior art communication systems, a first wireless communication device, such as a cellular telephone, may initiate communications with a second wireless communication device. Communications between the two wireless communication devices are generally accomplished using a fixed transceiver, commonly referred to as a base station. When the first wireless communication device initiates communications with the second wireless communication device, it does so by transmitting one or more initial message(s), for example, an origination message, to the fixed transceiver. The initial message(s) typically contains various information, such as an identification of the first wireless communication device (a mobile identification number (MIN), an electronic serial number (ESN), an international mobile subscriber identification (IMSI) number, etc), position-related information of the wireless communication device, an identification of the second wireless communication device, the type of communications desired (for example, secure voice, secure data, clear voice, clear data), and so on.
In many instances, it may not be desirable to allow the information contained in the initial message(s) to be received by an unauthorized recipient. For example, it may be desirable to keep a user's identity secret during all portions of a wireless communication, including the transmission of one or more initial messages.
One method for protecting a user's identity during transmission of an initial message(s) involves the use of a temporary user identification code, sometimes referred to as a Temporary Mobile Subscriber Identity, or (TMSI), to protect a device's identification code, such as an IMSI. In this case, a user transmits one or more initial messages, including the IMSI, and is then provided a TMSI for use during subsequent communications. The TMSI is usually transmitted over an encrypted channel to the requesting communication device, so that an unauthorized recipient cannot intercept it. The TMSI is then used in subsequent communications to identify the communication device.
The disadvantage of the security method described above, of course, is that the first wireless communication device must at least one time send the IMSI, or other identifier, over the air for anyone to intercept. This means that the identifier and/or a number of informational items, such as a wireless communication device identification number, position-related information, etc., may be compromised, thus jeopardizing the security or anonymity of the first and/or possibly second wireless communication devices.
That is needed is a method and apparatus for initiating secure communications by a wireless communication device without compromising a user's identity and other characteristics normally transmitted during a request to initiate communications, while still allowing the fixed transceiver to determine the identity and other characteristics.